Current through Register Vol. 54, No. 50, December 14, 2024
Section 7.144 - Overhead support(a) Machinery and sheaves shall be so supported and secured as to effectually prevent any part becoming loose or displaced. The supporting beams shall be composed of steel, sound timber or reinforced concrete.(b) In computing the loads on overhead beams and their supports, the total load on overhead beams shall be assumed to be equal to the weight of all apparatus resting on the beams plus twice the maximum load suspended from the beams. The object in doubling the suspended load is to allow for impact, acceleration, stresses and the like. The load resting on the beams shall include the complete weights of the machine, sheaves, controller and the like. The load suspended from the beams shall include the sum of the tensions of all cables suspended from the beams.(c) No elevator machinery or sheaves may be fastened to the underside of the supporting beams at the top of the hoistway, except the idler or deflecting sheaves with their guards and frames. Supporting members for sheaves and other elevator machinery hung underneath beams may not be of cast iron in tension.(d) The factor of safety for overhead beams and their supports shall be five for steel and six for timber and reinforced concrete.